Skip to main content
New! Browse Circulars by Event, Advanced Search, Sample Codes, Schema Release. See news and announcements

GCN Circulars

GCN Circulars are rapid astronomical bulletins submitted by and distributed to community members worldwide. They are used to share discoveries, observations, quantitative near-term predictions, requests for follow-up observations, or future observing plans related to high-energy, multi-messenger, and variable or transient astrophysical events. See the documentation for help with subscribing to or submitting Circulars.

Search for Circulars by submitter, subject, or body text (e.g. 'Fermi GRB').
To navigate to a specific circular, enter the associated Circular ID (e.g. 'gcn123', 'Circular 123', or '123').
Advanced Search

To narrow the search results, use advanced search syntax. This allows for specifying which circular field to search (submitter, subject, and/or body). For additional information, refer to the advanced search documentation.

Advanced Search Examples (click to copy):

subject:"Swift"
body:"GRB"
submitter:"Judith Racusin"

25026 results found.

  1. GRB 991014, Optical Observations
  2. GRB 991014 - BeppoSAX NFI observations
  3. GRB 991014, radio observations
  4. GRB 991014, Optical Observations
  5. GRB 991014, optical observations
  6. GRB 990915 optical observations
  7. Optical Observations of GRB990907
  8. GRB990907: BeppoSAX follow up and X-ray afterglow
  9. GRB990907 and 990908
  10. GRB 990712 Late Optical Decay and Host Galaxy
  11. GRB990806 BeppoSAX follow up
  12. GRB990806: BATSE Observations
  13. GRB 990806 Optical observations
  14. GRB 990806, Optical Observations
  15. GRB 990806, optical observations
  16. GRB 990806, Optical Observations
  17. GRB990806 UBVRIJHK observations
  18. GRB 990712 Optical Observations
  19. GRB 990712
  20. Late-time HST/STIS Observations of GRB 990510
  21. BeppoSAX NFI Observation of GRB990705
  22. BeppoSAX NFI Observation of GRB990705
  23. GRB 990705, R-band observations
  24. Infrared and Optical Observations of GRB990705
  25. GRB990704: SAX-NFI results summary
  26. GRB990704 radio and optical observations
  27. GRB990704
  28. GRB990704, optical observations
  29. BeppoSAX NFI Observation of GRB990627 X-ray afterglow
  30. Optical Observations of GRB990627
  31. BeppoSAX: GRB990625
  32. Late-time HST/STIS Observation of GRB 990123
  33. Optical Observations of GRB 990506
  34. GRB990527 Optical Observations
  35. X-ray/GRB 1SAX J0835.9+5118, Optical Observation
  36. Late Afterglows of GRBs 990510, 990123
  37. X-ray/GRB 1SAX J0835.9+5118, TNG V and R observations
  38. X-ray/GRB 1SAX J0835.9+5118, BATSE Observation
  39. X-ray/GRB 1SAX J0835.9+5118, Optical Observations
  40. X-ray/GRB 1SAX J0835.9+5118, Optical Observation
  41. X-ray/GRB 1SAX J0835.9+5118, Optical Observation
  42. X-ray/GRB 1SAX J0835.9+5118, Optical Observation
  43. radio observations of X-ray/GRB transient field
  44. optical observation of the X-ray/GRB transient SAX J0835.9+5118
  45. Optical report on X-ray/GRB transient
  46. radio detection of X-ray/GRB transient
  47. BeppoSAX: A new fast X-ray transient
  48. GRB 990510: optical observations
  49. GRB 990510: optical linear polarization
  50. GRB 990510: optical observations
  51. GRB990510: X-ray afterglow
  52. GRB 990510: Broad Band Break
  53. GRB 990510: BATSE Observations
  54. GRB 990510: BeppoSAX/GRBM observations
  55. GRB990510 optical observations
  56. GRB 990510 optical observations
  57. GRB 990506 Radio Observations
  58. GRB 990123, optical monitoring
  59. GRB 990506: BATSE Observations
  60. GRB 990506, optical observations
  61. GRB 990506, Optical Observations
  62. GRB 990506 optical observations
  63. GRB 990506, optical observations
  64. GRB 990506, armchair astronomy
  65. GRB 990506, optical observations from +1 to +3 hours
  66. GRB 990506, optical observations
  67. GRB990506 observation plan
  68. IPN localization for GRB990506
  69. GRB990323 PRECISE IPN POSITION
  70. GRB 990316 Optical Observations
  71. GRB 990316 optical observations
  72. GRB990316: simultaneous optical observation
  73. GRB990316 - Optical null results
  74. GRB990308 not a new SGR
  75. GRB 990308a and GRB 990308b
  76. GRB990308, Possible new SGR~0209+70
  77. GRB 990123, Field Photometry
  78. GRB 990217 Optical Observations
  79. BATSE Flight Anomaly
  80. GRB990217: BeppoSAX/GRBM data
  81. GRB990123 observations
  82. GRB990217 Optical observation
  83. GRB990123, Optical Observation
  84. GRB 990123: Discovery of the Probable Host Galaxy
  85. GRB 990123: Reduced HST Images
  86. GRB19990123 observations
  87. GRB 990123: BVRI standards in the field
  88. GRB981220, field photometry
  89. GRB990123, Optical observation
  90. GRB990123, 15-GHz limits
  91. GRB 990123: New Constraints on Possible Foreground Galaxies
  92. GRB990123 Optical Observations
  93. GRB990123, Probability of gravitational lensing
  94. GRB 990123: Detection of the IR Transient, and the Light Curve Fits
  95. GRB990123, Preliminary Lens Search Results
  96. On the Lensing Interpretation of GRB 990123
  97. Search for Potential Images of GRB 990123
  98. Search for Potential Images of GRB 990123
  99. GRB990123, Optical BVRI Observations
  100. GRB 990123: near-infrared observations.

Advanced

Download all Circulars as a .tar.gz archive:
Questions or comments?
Contact GCN directly.
Have you found a bug in GCN?
Open an issue.
Want to contribute code to GCN?
Get involved on GitHub.

gcn.nasa.gov

A service of the Astrophysics Science Division at NASA Goddard Space Flight Center

Looking for U.S. government information and services? Visit USA.gov